Support blocked parent storage in fixed patch stepping

tests/validation/multigrid/test_refinement_followup.py

@@ -111,7 +111,7 @@ class FaultGuardsCPU(unittest.TestCase):
         backend._lock = RLock()
         backend._status = "ready"
         backend._stream = Mock()
-        backend._levels = [Mock(shape=(9, 1, 1)), Mock(shape=(9, 1, 1))]
+        backend._levels = [Mock(shape=(9, 1, 1), layout=None), Mock(shape=(9, 1, 1), layout=None)]
         backend._allocations = [Mock(), Mock()]
         return backend